Image MIME Reference
Kodak-K25
Kodak K25 Raw Image
image/x-kodak-k25
VS
Portable Pixmap
image/x-portable-pixmap
PPM
A complete technical comparison of Kodak K25 Raw Image and Portable Pixmap — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Kodak-K25 | PPM |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
Kodak K25 Raw Image
image/x-kodak-k25
Extension
.k25
Container
Proprietary Kodak Raw (TIFF-based variant)
Compression
Uncompressed / Proprietary Lossless
Algorithm
Proprietary Kodak Compression
Color Depth
10-bit, 12-bit (Per Channel)
Developed by
Eastman Kodak Company
Released
1996
Magic Bytes
Varies (Often resembles TIFF header 49 49 2A 00 or requires proprietary parsing)
Portable Pixmap
image/x-portable-pixmap
Extension
.ppm
Container
Netpbm
Compression
Uncompressed
Algorithm
None
Color Depth
24-bit (RGB), 48-bit (RGB High Color)
Developed by
Jef Poskanzer (Netpbm Project)
Released
1988
Magic Bytes
50 33 (ASCII) or 50 36 (Binary)
Browser Support Comparison
| Browser | Kodak-K25 | PPM |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
Kodak-K25
Kodak-K25 Strengths
- Historically significant format tied to the first digital camera to adopt CompactFlash memory
- Preserves original raw sensor data, allowing modern demosaicing algorithms (via LibRaw) to extract much better image quality than 1996-era software could
Limitations
- Completely obsolete and deeply proprietary, lacking modern raw format features found in DNG
- Cannot be natively viewed in web browsers or standard operating system image viewers without specialized decoders
- Subject to misidentification by automated MIME detection libraries due to structural similarities with standard TIFFs
PPM
PPM Strengths
- Absolute structural simplicity allows parsers and renderers (such as custom raytracers) to write directly to the format with virtually no overhead or external libraries
- Supports 16-bit per channel (48-bit total) precision, preserving deep color accuracy before converting to final delivery formats
- ASCII encoding ('P3') allows manual editing and visual inspection of RGB values directly within a text editor
Limitations
- Zero compression results in astronomical file sizes, making it entirely impractical for web delivery or consumer storage
- Does not natively support an alpha channel for transparency (this is handled by the newer PAM extension format within the Netpbm suite)
- Lacks support for modern metadata standards like EXIF, XMP, or embedded ICC color profiles
When to choose which format
Kodak-K25
Use Kodak-K25 when…
- Vintage Digital Photography Archival
- Kodak DC25 Camera Restorations
- Historical Imaging Research
PPM
Use PPM when…
- Intermediary Format for Image Format Conversion
- Academic Computer Graphics and Raytracing Output
- Unix/Linux Command-Line Image Pipelines